The efficacy of salvage treatments in 243 patients with operable breast cancer and positive axillary nodes who failed during or after adjuvant chemotherapy with CMF (cyclophosphamide, methotrexate and fluorouracil) was analyzed. Results were compared with those achieved in 100 patients who had relapses after radical mastectomy alone (control group). Salvage treatments consisted primarily of endocrine therapy (castration in premenopausal patients and tamoxifen in postmenopausal women) and chemotherapy (CMF or Adriamycin [doxorubicin] regimens). In 20 patients, however, first salvage treatment consisted of local therapy only (i.e., radiation therapy with or without surgery). In women previously treated with adjuvant CMF, complete plus partial remissions after first salvage treatment were 37% with a median duration of 17 months. In the control group, the response rate was 43% with a median duration of 16 months. The findings also indicated that drug-induced amenorrhea did not lower the objective response to salvage castration. In patients failing with a disease-free interval in excess of 12 months from end of adjuvant CMF, retreatment with the same combination was able to induce remission in 52% of the patients. Current data, derived from prospective controlled studies, confirm that, despite relatively high remission rates, all forms of salvage treatment failed to provide, in unselected cases, long-term control of relapsed breast cancer. Most important, prior adjuvant chemotherapy with CMF did not adversely affect results compared to concomitant controls.